The worst-case cost for Radix Sort when
sorting n keys with keys in the range 0 to r^3-1 is:
\Theta(n)\Theta(n \log n)\Theta(n^2)\Theta(n^3)In this question, we restricted the key range.
We restrict the key range to be a constant number of digits, independent of the number of records.
So, each record is processed three times.